Protection of polyamide fibers during treatment with peroxide containing bleaching or washing agents



United States Patent PROTECTION OF POLYAMIDE FIBERS DURING TREATMENT WITH PEROXIDE CONTAINING BLEACHING 0R WASHING AGENTS Karl Dithmar and Elfriede Naujoks, Frankfurt, Germany, assignors to Deutsche Goldund Silber-Scheideanstalt vormals Roessler, Frankfurt am Main, Germany No Drawing. Application March 11, 1954 Serial No. 419,911

Claims priority, application Germany March 12, 1953 3 Claims. (Cl. 8-111) The present invention relates to an improved process for treating polyamide fibers, such as, nylon or Perlon fibers with peroxide containing bleaching or washing agents wherein attack on such fibers is minimized.

It is well known that polyamide fibers are strongly attacked during treatment in bleaching or washing baths containing peroxide with the result of a considerable loss of strength of s h fibers. For exampi', the loss in tensile strength polyamide fibers sold under the trade name Perlon can amount to 40% to 80% of their original tensile strength, when such fibers are subjected to the action of peroxide containing bleaching or washing baths at high temperatures for any substantial length of time as may occur in order to obtain satisfactory bleaching effects in polyamide fiber containing mixed fabrics or when polyamide fiber containing products are washed from time to time after having become soiled. Even though the washing or bleaching baths have been stabilized with magnesium silicate, phosphates or other materials which retard the spontaneous evolution of oxygen, the same damage to polyamide fibers occurs during their use.

In accordance with the invention, it was unexpectedly found that such loss in tensile strength of polyamide fibers during bleaching or washing with peroxide containing baths, could be substantially avoided in a simple manner by incorporating small quantities of protective agents in such baths.

The protective agents employed according to the invention are organic nitrogen compounds or their salts which contain at least two nitrogen atoms of which at least one is in the form of a primary or secondary amino group and the second of which can be of the same nature, or also be a tertiary amino group or a sulfonamide group. The nitrogen containing groups should be connected through a preponderantly saturated hydrocarbon chain which contains no more than 6 carbon atoms, such hydro carbon chain can also be interrupted by hetero-atoms or they can be connected through a chain forming part of a ring structure, which is of saturated or aromatic nature. Suitable protective substances according to the invention are for example as follows:

Ethylene diamine NH -CH CH -NH Hexamethylene diamine na-( H2) 6 2 Triethylene tetramine z( 2)z- 2( z)2 z( z)2 2' N-carboxy ethylene diamine NH CH CH NHCOOH Piperazine CH2-CH2 HN/ \NH GHQ-0H. N,N' dimethyl-p-phenylene diamine om-NHGNrr-on.

N,N dimethyl-p-phenylene diamine 2-methyl benzimidazole C-CH The protective agents according to the invention have been found considerably more active than protective agents previously suggested and, consequently, are effective at considerably lower concentrations both in bleaching baths as well as washing. For example, in bleaching baths containing an active oxygen content of 0.3 mol per liter the protective agents according to the invention give good protection action at concentrations between 0.01 mol and 0.05 mol per liter even strongly aggressive alkaline bleaching baths. In usual peroxide containing washing baths which normally contain no more than about 0.25 g. of active oxygen per liter, the quantity of protective agent employed, according to the invention, to provide good protective action, can be reduced to about 0.001 to 0.005 mol per liter.

When the protective agents according to the invention, are added to peroxide bleaching baths containing the normal ingredients, such as soluble silicates, magnesium sili cate or other peroxide stabilizers, alkalies, normal or anhydrous phosphates, soaps or washing agents, surface active agents, wetting agents and the like, a very good protective action upon the polyamide fibers treated in such baths, as when such protective agents are added, the normally expected 40 to loss in strength by the polyamide fibers is reduced to only about 2 to 8% A further advantage of the protective agents employed in accordance with the invention, is that in most instances they support the bleaching power of peroxide bleaching or washing baths and undesired discolorations of the fibers are avoided. It is of course known that some organic compounds containing two nitrogen atoms, such as, for example, those of the por o-phenylene diamine series can become discolored under the action of oxidizing agents. However, such compounds also have the property of protecting polyamide fibers against the deleterious action of peroxide containing baths so thabundesirable loss in strength of such fibers is avoided. Consequently, such compounds also come within the purview of the invention, despite the fact, that their utility is naturally limited in view of their propensity to discolorations.

The following examples will serve to illustrate several modifications of the invention.

Example 1 A yarn of 60 denier Perlon L filaments was treated with movement for two hours at 60 C. in a bath of the following composition:

4.8 g. per liter of active oxygen in the form of H 0;

(0.3 mol) 0.1 g. per liter crystalline magnesium sulfate 1.0 cc. per liter commercial water glass 38 B.

1.72 g. per liter pipcrazine (0.02 mol) 3 The pH value of such bath was 9.5 and the ratio of yarn to bath was 1:50. After conclusion of the bleaching treatment, the bleaching bath still contained 3.8 g. of active oxygen per liter.

The tearing strength of the Perlon L polyamide yarn was originally 40.2 kilometers (that is, it would sup- .port a weight equivalent to a length of such yarn 40.2 kilometers long before rupture). After the five hours treatment in the bleaching bath, its strength had only decreased to 37 kilometers or in other words, had only suffered a loss in strength of 8% of the original strength.

When on the other hand Perlon L yarn was treated in a bath of the same composition under the same conditions, except that the protective agent, namely, piperazine, was omittedfrom the bath, the yarn suffered a 38% loss in strength after two hours treatment.

Example 2 A polyamide artificial silk fabric produced from 60 denier filaments was bleached in a reel vat at 60 C. for three hours in an aqueous bleaching bath of the following composition:

4.8 g. per liter active oxygen in the form of H 0.1 g. per liter magnesium sulfate 1.0 cc. per liter commercial water glass 38 B. 1.7 g. per literj-aminobenzene sulfonamide The pH value of such bath was 9.1 and the ratio of fabric to bath was 1:60. After completion of the bleaching treatment, the bath still contained 4.0 g. per liter of active oxygen.

The three hours bleaching treatment only lowered the tearing strength of the polyamide artificial silk from 43.1 kilometers to 42 kilometers and consequently caused only a 2.5% loss in strength.

Example 3 Piece goods whose warp and weft were woven from polyamide artificial silk were treated on star reel at 60 C. for 2 hours in a bleaching bath of the following composition:

2.4 g. per liter of active oxygen in the form of H 0 0.1 g. per liter of magnesium sulfate 1.0 cc. per liter of sodium water glass containing 25% SiO,

1.5 g. per liter of ethylene diamine oxalate 0.2 per liter of NaOH The pH value of such bath was 9.2 and the ratio of fabric to bath was 1:150. After completion of the bleaching treatment, the bath still contained 2.0 g. per liter of active oxygen.

The two hours bleaching treatment only lowered the tearing strength of the warp from 43.5 kilometers to 40 kilometers and consequently only caused a 7.8% loss in strength.

Example 4 A mixed fabric woven with a warp of 60 denier polyamide artificial silk and a weft of 100 denier viscose artificial silk was treated in loose form with movement at 60 C. for two hours in a bleaching bath of the following composition:

4.8 g. per liter active oxygen in the form of H 0 0.1 g. per liter magnesium sulfate 1.0 cc. per liter commercial water glass 1.0 g. per liter N-carboxyethylenediamine The pH value of such bath was 9.1 and the ratio of fabric to bath was 1:40. During the bleaching treatment the active oxygen content of the bath decreased from 4.8 to 4.2 g. per liter.

The two hours treatment produced a good bleaching effect and only lowered the tearing strength of the warp from 44.2 kilometers to 42.2 kilometers and consequently only caused a 4.5% less in strength.

4 Example 5 A woven fabric produced from 60 denier polyamide artificial silk yarn was treated at 60 C. for two and one half hours in a bath of the following composition:

4.8 g. per liter active oxygen in the form of H 0 0.1 g. per liter magnesium sulfate 1.0 cc. per liter commercial 38 B. water glass 1.5 g. per liter triethylenetetramine In this and the following examples typical laundering conditions were employed. In such baths the quantity of active oxygen amounts to only about one twentieth of that contained in the usual bleaching baths. In view of this, it was possible to reduce the quantity of the protective agents employed considerably.

Wash goods woven of 60 denier polyamide artificial silk were washed in a washing machine for two hours at C. in an aqueous washing liquid of the following composition:

G. per liter Sodium perborate 2.5 Soap powder 4.5 Dry water glass 0.2 Sodium bicarbonate 0.5 Sodium carbonate 1.2 Neutral sodium pyrophosphate 1.1 p-Amino benzene sulfonamide 0.2

After this two hours (intentionally somewhat lengthy) washing treatment, the tearing strength of the wash goods was only lowered from 46 to 45.1 kilometers and consequently such goods suffered only a 2% loss in strength.

In contrast thereto, when wash goods were washed under the same conditions in the same bath, but omitting the protective agent, p-aminobenzene sulfonarnide, its tearing strength was lowered from 46 to 36.5 kilometers and consequently it sufiered a 20.7% loss in strength.

Example 7 Wash goods woven of polyamide artificial silk were washed at 60 C. (with light movement of the wash goods) in a washing liquid of the following composition:

G. per liter Sodium perborate 2.5 Soap powder 4.5 Dry water glass 0.2 Sodium carbonate 1.2 Sodium bicarbonate 0.5 Neutral sodium pyrophosphate 1.1

N-carbamic acid salt of ethylene diamine 0.04

The ratio of goods to washing liquid was 1:50.

After four hours of such washing treatment, the tearing strength of the polyamide threads decreased from 46 to 44.28 kilometers and after eight hours of such washing treatment the tearing strength decreased to 43.47 kilometers. Consequently the loss in strength after four hours washing treatment amounted to only 3.7% and after eight hours only 4.8%.

In comparison polyamide wash goods, when washed under the same conditions and in the same washing liquid except that the protective agent had been omitted, suffered a 21% loss in strength after four hours washing and 36.1% after eight hours washing.

Example 8 Wash goods woven of pclyamide artificial silk (Perlon- L-artificial silk) were washed at a temperature of 80 C. for one hour in an aqueous washing liquid containing g. per liter of a washing powder of the following composition:

% sodium perborate 45% soap powder 2% water glass 12% sodium carbonate 5% sodium bicarbonate 10.5% neutral sodium pyrophosphate 0.5% Z-methyl benzimidazole The pH value of the washing bath was 10.0 and the ratio of goods to bath was 1:30. After the washing treatment was completed the wash goods were rinsed in the usual manner with running water.

After such one hours washing treatment, the tearing strength of the wash goods decreased from 43.0 to 42.0 kilometers and consequently only lost 2.3% of its strength.

In comparison when such wash goods were washed under the same conditions and in the same washing liquid except that the 2-methylbenzimidazole had been omitted, they sufiered a 16% loss in strength.

g Example 9 A polyamide artificial silk fabric woven of 60 denier Perlon-L-silk was washed for two hours at 90 C. in an aqueous washing liquid of the following composition:

After such washing treatment, the tearing strength of the fabric decreased only from 45.0 to 43.11 kilometers and consequently the fabric only suffered a 4.2% loss in strength.

In comparison when such a fabric was washed under the same conditions and in the same washing liquid except that the N,N' phenylethylene diamine had been omitted, the fabric sufiered a 20.7% loss in strength.

The term peroxide as used herein, not only denotes peroxides, such as sodium peroxide and hydrogen peroxide, but also such compounds as sodium perborate, sodium percarbonate, sodium perpyrophosphate which form hydrogen peroxide in aqueous solution.

We claim:

1. In a process for the treatment of materials containing polyamide synthetic fibers with an aqueous solution containing a peroxide in a quantity to provide an active oxygen content of up to about 5 g. per liter, the step which comprises incorporating in such aqueous solution 0.001 to 0.05 mole per liter an organic compound containing at least two nitrogen atoms of which at least one is in the form of an amino group selected from the group consisting of primary and secondary amino groups and any other is in the form of a group selected from the group consisting of pn'mary amino, secondary amino and tertiary amino groups, said nitrogen atoms being linked together by a chain containing up to 6 carbon atoms, the quantity of organic compound incorporated being sufficient to afford substantial protection of the fibers against deterioration during the treatment with the aqueous peroxide containing solution.

2. In a process for bleaching materials containing synthetic polyamide fibers with an aqueous bleaching solution containing a peroxide in a quantity to provide an active oxygen content of up to about 5 g. per liter, the step which comprises incorporating in such aqueous bleaching solution 0.001 to 0.05 mole per liter an organic compound containing at least two nitrogen atoms of which at least one is in the form of an amino group selected from the group consisting of primary and secondary amino groups and any other is in the form of a group selected from the group consisting of primary amino, secondary amino and tertiary amino groups, said nitrogen atoms being linked together by a chain containing up to 6 carbon atoms, the quantity of organic compound incorporated being sufficient to afford substantial protection of the fibers against deterioration during the treatment with the aqueous peroxide containing solution.

3. In a process for washing materials containing synthetic polyamide fibers with an aqueous washing solution containing a peroxide in a quantity to provide an active oxygen content of up to about 0.25 g. per liter, the step which comprises incorporating in such aqueous washing solution 0.001 to 0.005 mole per liter an organic compound containing at least two nitrogen atoms of which at least one is in the form of an amino group selected from the group consisting of primary and sec: ondary amino groups and any other is in the form of a group selected from the group consisting of primary amino, secondary amino and tertiary amino groups, said nitrogen atoms being linked together by a chain containing up to 6 carbon atoms, the quantity of organic compound incorporated being sufiicient to afford substantial protection of the fibers against deterioration during the treatment with the aqueous peroxide containing solution.

References Cited in the file of this patent UNITED STATES PATENTS 2,153,416 Frenkel Apr. 4, 1939 2,287,099 Hardy June 23, 1942 2,308,992 Mertens Jan. 19, 1943 2,412,945 Bersworth .Dec. 24, 1946 2,543,852 JaCcard Mar. 6, 1951 2,688,617 Hein et a1. Sept. 7, 1954 2,730,428 Linder Jan. 10, 1956 2,778,827 Ackermann Jan. 22, 1957 OTHER REFERENCES Turnbull: Dyeing of Broad-Woven Nylon Fabrics, Am. Dyest. Rptr., October 17, 1949, p. 747.

Folgner: Organic Hydrogen Peroxide Stabilizers in Bleaching, Monatsh. f. Textil-Ind., vol. 52, 1937, pp. 257-259, thru Am. Dyestufi. Reptr., August 22, 1938, pp. 476, 477.

Sequestrene, pp. 48, 49, 54, pub. by Alrose Chem. C0., Providence (1952). 

1. IN A PROCESS FOR THE TREAMENT OF MATERIALS CONTAINING POLYAMIDE SYNTHETIC FIBERS WITH AN AQUEOUS SOLUTION CONTAINING A PEROXIDE IN A QUANTITY TO PROVIDE AN ACTIVE OXYGEN CONTENT OF UP TO ABOUT 5G. PER LITER, THE STEP WHICH COMPRISES INCORPORATING IN SUCH AQUEOUS SOLUTION 0.001 TO 0.05 MOLE PER LITER AN ORGANIC COMPOUND CONTAINING AT LEAST TWO NITROGEN ATOMS OF WHICH AT LEAST ONE IS IN THE FORM OF AN AMINO GROUP SELECTED FROM THE GROUP CONSISTING OF PRIMARY AND SECONDARY AMINO GROUPS AND ANY OTHER IS IN THE FORM OF A GROUP SELECTED FROM THE GROUP CONSISTING OF PRIMARY AMINO, SECONDARY AMINO AND TERTIARY AMINO GROUPS, SAID NITROGEN ATOMS BEING LINKED TOGETHER BY A CHAIN CONTAINING UP TO 6 CARBON ATOMS, THE QUANTITY OF ORGANIC COMPOUND INCORPORATED BEING SUFDETERIORATION DURING THE TREAMENT WITH THE AQUEOUS PEROXIDE CONTAINING SOLUTION. 